Extended Abstract
Bachelor Thesis, Department of International Development Engineering, Tokyo Institute of Technology, 2002
Conversion and Recycle of Wood Residues in Rubber Wood Process
KEAN GIAP LIM
Student ID: 98-2985-2
Supervisor: RYUICHI EGASHIRA
Department of International Development Engineering,
Faculty of Engineering,
Tokyo Institute of Technology, Tokyo 152-8552, Japan
1.
Introduction
Wood VinegarLv
,
Furniture Part
F7
W7
Separation
S7
Boiler Fuel WBF
W1,SB
Disposal
S6
S5
S4
W4
Coloring
Adhesion
Molding (6)
Grinding (5)
Quality Control (4)
W6
F6
Softboard Rawmaterial
RSB
Sawdust S, 1
S1,SB
S1,SC
Fig.1
Rsc
Dry Distillation
W1,BF
W1,SC
F5
Wood TarLT
Crude
Wood vinegarLD
Waste
Wood W1
F4
F3
Mold・Q.C. (7)
Treatment Waste
Lw
F2
BandSaw (1)
F1
Wood
PreservativesLp
Kiln.Drying (3)
Rubber Wood
Logs F0
Treatment (2)
In Southeast Asia Countries, rubber wood is
processed to manufacture the parts of household
furniture. A typical timber process in these countries at
present is shown in Figure1 (enveloped by thin line). In
this process, a portion of wood residues are being
thrown away to isolated country site or dumping site
and it is burned at open area, both legally and illegally.
These methods of disposal do cause accidental forest
burning and release of hazardous gases into the
environment[1]. Besides, many of the chemical
preservatives being used in preventing the wood
products against fungus, molds, and termites are highly
toxic and can easily diffuse into the environment[2].
These problems are quite serious in these countries. By
the way, wood vinegar, which is obtained by pyrolysis
or carbonization of wood, have the potential of
preserving wood[3,4].
CharcoalRD
2.
Characterization of Wood Vinegar from
Rubber Wood
2.1 Experimental
Crude wood vinegar (CWV) used in this study was
obtained from Malaysia charcoal factory. The vinegar
was collected under natural condensation of the smoke
while carbonization of rubber logs and sawn waste
wood. The sample is reddish brown in color.
Simple distillation of CWV was carried out to
remove the tar fraction and to obtain the wood vinegar
(WV). Density and pH value of the WV samples were
determined using standard hydrometer and glass
conductor pH meter, respectively. The WVs and tar
were analyzed by a gas chromatograph (FID) with a
capillary column to determine mass fractions of the
components shown in Table 1, which are preservatives
and a Karl Fishcer titrator to determine water content.
2.2 Results and discussion
The density, pH, water content, and tar content of
the CWV are summarized in Table 2. The experimental
values of density, pH, and water content fell within the
ranges prescribed[5,6]. The CWV used in this study had
similar physical properties as typical CWV. From
simple distillation of CWV, result shows that CWV
from rubber wood contain 2% wood tar. This result also
fell within the acceptable range.
Table 1 Components contained in wood vinegar from
rubber wood
Schematic diagram of rubber wood process
The aim of this study is to improve the rubber
wood process by conversion of the wood residues to
wood vinegar preservative and the recycle of this. In the
first stage, the wood vinegar from rubber wood was
characterized, especially to examine the preservative
properties. In the second, the rubber wood process was
improved and was simulated to study its viability.
Component
Mass fraction in CWV
[–]
Acetone
Methanol
Acetic Acid
Guaiacol
Phenol
O-cresol
M-cresol
P-cresol
Syringol
0.0008
0.0016
0.0422
0.0005
0.0005
0.0004
0.0001
0.0004
0.0019
Fractional recovery
by distillation [–]
in WV
in Tar
0.53
0.47
1.00
0.00
0.96
0.04
0.98
0.02
0.99
0.01
0.44
0.56
0.52
0.48
0.24
0.76
0.25
0.75
Table 2 Physical properties of CWV
Received on February 22, 2002. Correspondence concerning this
article should be addressed to Kean Giap Lim (E-mail address:
kglim@ide.titech.ac.jp).
Density [g·cm–3]
pH
Water content [–]
Tar content [–]
This work
1.014
2.98
0.87
0.02
Previous work[3,6]
1~1.050
1.97~3.49
0.8~0.9
0.02~0.11
Tokyo Institute of Technology
Table 3 Principal parameters used for calculation
Component recovery,[-]
1 .0
Parameter (definition)
α1 (=F1/F0)
[–]
α4 (=F4/F3)
[–]
α5 (=F5/F4)
[–]
α6 (=F6/F5)
[–]
[–]
α7 (=F7/F6)
[–]
β1 (=W1/F0)
β6 (=W6/F5)
[–]
[–]
β7 (=W7/F6)
[–]
γ4 (=S4/F3)
ω2 (=LP/F1)
[–]
φ1,BF (=W1,BF/W1)
[–]
[–]
φ1,SB (=W1,SB/W1)
XD (=LD/RSC)
[–]
[–]
XV (=LV/LD)
Ace ton e
Me th an ol
Ace ti c Aci d
Gu aiacol
Ph e n ol
O -cre sol
P-cre sol
M-cre sol
S yri n gol
0 .8
0 .6
0 .4
0 .2
0 .0
100
Fig.2
102
104
106
Te m pe ra tu re ,[ ℃ ]
108
110
Fractional recovery by distillation
The WV compositions and fraction recovery are
shown in Tab. 1.The composition recovered at different
temperatures are shown in Figure 2.The most abundant
component in wood vinegar is acetic acid. This is likely
to be responsible for the high level of acidity of the
CWV as indicated by it’s pH value. In preservative,
aldehydes or ketones react with phenols to form a layer
of membrane on wood surface. This membrane prevents
water from getting in contact with the wood, which is
necessary condition for bacillus to survive. Guaiacol
and Syringol are also a kind of natural preservative to
wood. Both compositions are originally contained in
tree itself[7]. Cresols also have been reported as an
ingredient in preservatives.
Regarding to the preservative compositions
recovery result, the first and last fractions were
collected at 100 °C and 109 °C respectively. Fig.2
shows that complete separation of the WV was
accomplished at 109 °C. This indicated that simple
distillation can be used successfully in separating the
preservative compositions from wood tar.
These experimental results showed that WV from
rubber wood has potential of wood preservatives.
3.
Improvement of Rubber Wood Process
3.1 Outline of the process
The improved process is shown also in Fig.1. The
rubber wood residues are carbonized to produce CWV
and charcoal (dry distillation). This CWV is separated
into the WV and tar fraction by distillation. Thus
obtained WV is recycled to the treatment step in the
process as a preservative. By this conversion and
recycle, the amounts of dumping and burning wood
residues and harmful preservative effluents can be
reduced.
3.2 Equations for the process and calculation
The basic equations are the simple material
balances (omitted here) and is defined in Table 3.
The principal assumptions, specifications and
conditions are shown in Table 3. The ω2 and XV were
estimated from the above experimental result of the
density and fraction of WV in CWV, respectively. The
flow rate of the feed rubber wood, F0, was fixed at
1.6×106 t·year–1[8].
Under these specifications and conditions, the
0.15~0.20
0.97
0.95
0.85
0.97
0.77
0.13
0.02
1.1×10–3~6.6×10–3
0.10
0.40~0.80
0.20
0.15
0.98
Table 4 Principal results of calculation
α1
γ4
φ1,BF
F0
RSC
LV
LP
[–]
[–]
[–]
[t·yr–1]
[t·yr–1]
[t·yr–1]
[t·yr–1]
0.20
1.1×10-3
0.60
1.60×106
3.56×105
5.20×104
3.29×104
mass flow rate of wood vinegar that can be produced,
LV, that of wood preservatives, LP, and so forth were
calculated and were compared with each other.
3.3 Results and discussion
An example set of calculated results are
summarized in Table 4. The mass flow rate of wood
vinegar from wood residues, LV, were comparable with
or larger than that of wood preservatives required for
the treatment step, LP. Further, the energy balance etc.
should be estimated as well.
4.
Conclusion
The experimental results showed that the wood
vinegar prepared from rubber wood had the potential to
preserve woods. In the process calculation based upon
the experimental results, the rubber wood process could
be improved by conversion of the wood residues into
the wood vinegar and recycle of this. Consequently, this
was proposed as a way to solve environmental problem
in Southeast Asia countries.
Literature Cited
[1] “1999 Annual Report”, Department of Environment, Ministry of
Science, Technology and The Environment of Malaysia
[2] S. Tanjore, T. Viraraghavan; “Pentachlorophenol Water pollution
impacts and removal technologies”, Intern. J. Environ. Studies,
45, 155-164 (1994)
[3] K. Fukuda, A. Kaneko, T. Haraguchi; “Effectiveness of wood
liquor in anti bacteria”, Mokuzaihozon, 17, 109-114 (1991)
[4] F. S. Nakayama, S. H. Vinyard, P. Chow, D. S. Bajwa, J. A.
Youngquist, J. H. Mueh., A. M. Krzysik; “Guayule as wood
preservative”, Indusrtrial Crops & Products, 14, 105-111 (2001)
[5] Kishimoto “Encyclopedia of charcoal & wood vinegar”,
Soshinsha, 1997
[6] Iwatani; “Power of charcoal”, Soshinsha, 1,7~9
[7] S. Jodai, S. Yano, T. Uehara; “Component of wood vinegar
liquors and their smoke flavors”, Mokuzaigakkaishi, 35, 555-563
(1989)
[8] “Malaysia Agricultural Directory Index 1988/1989”, Published by
Pantai Maju